1. Field of the Invention
The present invention relates to devices for the stabilization of the spinal column and, more particularly, to spine or spinal rods used in the stabilization of the spinal column.
2. Background Information
A significant portion of the population suffers from spinal problems. Such spinal problems may be attributable to disease, trauma and/or other event. In the case of degenerative disc disease, spinal trauma and the like, such conditions are often painful and/or physically deforming. Depending on the situation, the pain and complications caused by these conditions may require that one or more vertebra, facet joints, and/or intervertebral discs be removed from the spinal column. In these procedures, bone fusion is a common treatment used to facilitate the realignment and/or fixation of the remaining spinal elements.
Currently, two types of systems or assemblies are utilized for securing and/or stabilizing one or more vertebrae in order to achieve bone fusion. One type of spine stabilizing assembly generally includes two posterior vertebral plates disposed longitudinally on either side of the spinous processes. Each plate is attached between adjacent vertebra using bone anchoring elements, such as bone screws. Together, the plates provide a rigid vertebral fixation.
Another type of spine stabilizing assembly generally includes two posterior vertebral rods disposed longitudinally on either side of the vertebrae (e.g. the spinous processes thereof). Like the plates, these rods are attached between adjacent vertebrae using appropriate bone anchoring devices to achieve rigid vertebral fixation.
These spine stabilizing assemblies are also used to correct spinal deformities such as scoliosis or the like. For this use, such spine stabilizing assemblies may have spine rods that span two or more vertebrae.
A drawback of current spinal rods relates to reception and seating of the spinal rod into the spinal rod holder/bone anchor assembly. Particularly, current spinal rods are round and must be securely retained in the spinal rod holder for proper spinal stabilization. The contact area between the round spinal rod and the U-shaped spinal rod holder is sparse given the two configurations. This low amount of contact area does not allow a good seating of the spinal rod into the rod holder. The spinal rod may be subject to loading that occurs on the stabilizing assemblies and especially on the anchoring sites during normal activity. These loads may result in loosening of the assembly from the vertebrae or even breaking of the assembly if there is not proper seating of the spinal rod in the spinal rod holder.
In view of the above, it is evident that there is thus a need for a spinal rod that provides the greatest extent of contact with a spinal rod holder.
In view of the above, it is further evident that there is thus a need for a spinal rod that is more securely received in a spinal rod holder than current spinal rods.